1. Field of the Invention
This invention relates to a system for measuring temperature distribution in water using optical fibers.
2. Description of the Related Art
One conventional method for measuring temperature distribution in water is known as a slide method in which a transmission cable having a sensor unit slidably mounted thereon is suspended in the water and the sensor unit is conveyed up and down while the transmission cable is towed to obtain temperature information at predetermined water depths. The temperature information thus obtained is transmitted to a device on board a ship by utilizing electromagnetic coupling between the sensor unit and the transmission cable.
In another known method, a sensor chain is used which includes a plurality of sensor units mounted on a transmission cable in tiers. Each sensor is electromagnetically coupled to the transmission cable to transmit the temperature information to an on-board measuring device using a polling technique.
In the slide method, since the temperature at different water depth is measured while raising and lowering the sensor unit, it is impossible to continuously measure the temperature at a predetermined depth.
The sensor chain method also suffers a drawback in that an increased number of sensor units is used according to the number of measurement points. It is troublesome to mount and remove a great number of sensor units.